Acceleration of plastoquinone pool reduction by alternative pathways precedes a decrease in photosynthetic CO₂ assimilation in preheated barley leaves

In this: publication
By this: publisher
In this Subject: Botany
By this author: Ka&#328;a, Radek ;&nbsp; Kotabov&#225;, Eva ;&nbsp; <a href="/search?option2=author&value2=Pr%26%23225%3b%26%23353%3bil++Ond%26%23345%3bej">Pr&#225;&#353;il, Ond&#345;ej

Authors: Kaňa, Radek; Kotabová, Eva; Prášil, Ondřej

Source: Physiologia Plantarum, Volume 133, Number 4, August 2008 , pp. 794-806(13)

Buy & download fulltext article:

Price: $48.00 plus tax (Refund Policy)

Abstract:

Heat stress causes inhibition of photosynthetic CO₂ assimilation, affects light photosynthetic reactions and accelerates alternative pathways of plastoquinone pool reduction (APPR). We have studied all these heat-sensitive processes after preheating to a broad range of physiological temperatures (24-46°C) to explore a role of these alternative pathways during heat stress. Primarily, the effective quantum yield of PSII photochemistry was reduced (at 40°C). This PSII downregulation was accompanied by the stimulation of APPR and preceded reduction of photosynthetic CO₂ assimilation by 2°; it occurred after preheating at 42°C because of inhibition in Rubisco (ribulose 1,5-bisphosphate carboxylase/oxygenase) activation process. Thus, we suggest that the heat-induced stimulation of APPR is not associated with the heat-induced inhibition of Calvin cycle as it was reported for other types of stresses. A possible role of APPR in the compensation of PSII downregulation is briefly discussed.

Document Type: Research article

DOI: http://dx.doi.org/10.1111/j.1399-3054.2008.01094.x

Publication date: 2008-08-01